Question 1

The first step in hypothesis testing is always:

Accepted Answer

A)  formulating two opposing hypotheses, called the null and alternative hypotheses 
B)  selecting a test statistic 
C)  calculating the p-value 
D)  determining the rejection region 
E)  determining the critical value 
A)  formulating two opposing hypotheses, called the null and alternative hypotheses 
B)  selecting a test statistic 
C)  calculating the p-value 
D)  determining the rejection region 
E)  determining the critical value

Question 2

Which of the following is an example of a null hypothesis?

Accepted Answer

A)  This industrial process makes windshields with an average length of 33 inches. 
B)  The average quantity of detergent put into a box by this filling machine is not 1 pound. 
C)  This shipping company's average delivery time is different from 3 days. 
D)  The thickness of aluminum sheets averages is not .03 inches, as required. 
E)  The average quantity of detergent put into a box by this filling machine is not 1 pound and this shipping company's average delivery time is different from 3 days. 
A)  This industrial process makes windshields with an average length of 33 inches. 
B)  The average quantity of detergent put into a box by this filling machine is not 1 pound. 
C)  This shipping company's average delivery time is different from 3 days. 
D)  The thickness of aluminum sheets averages is not .03 inches, as required. 
E)  The average quantity of detergent put into a box by this filling machine is not 1 pound and this shipping company's average delivery time is different from 3 days.

Question 3

For a fixed sample size n, as the probability of a Type II error   decreases, the probability of a Type I error   increases.

Accepted Answer

A) True 
 B)False

Question 4

In testing   vs.   the level of significance must be twice as large as when testing   vs.   .

Accepted Answer

A) True 
 B)False

Question 5

A Type I error for a statistical test is committed if we reject the null hypothesis when it is true.

Accepted Answer

A) True 
 B)False

Question 6

If we reject the null hypothesis   , we conclude that there is not enough statistical evidence to infer that the population proportions are equal.

Accepted Answer

A) True 
 B)False

Question 7

Consider testing the hypothesis:   . If the value of the test statistic is equal to 1.36, then the p-value is:

Accepted Answer

A)  0.4131 
B)  0.1738 
C)  0.2066 
D)  0.9131 
E)  0.8325 
A)  0.4131 
B)  0.1738 
C)  0.2066 
D)  0.9131 
E)  0.8325

Question 8

In constructing a confidence interval estimate for the difference between two population proportions, we:

Accepted Answer

A)  pool the population proportions when the populations are normally distributed 
B)  pool the population proportions when the population means are equal 
C)  pool the population proportions when they are equal 
D)  never pool the population proportions to construct confidence interval for 
E)  always pool the population proportions to construct confidence interval for 
A)  pool the population proportions when the populations are normally distributed 
B)  pool the population proportions when the population means are equal 
C)  pool the population proportions when they are equal 
D)  never pool the population proportions to construct confidence interval for 
E)  always pool the population proportions to construct confidence interval for

Question 9

When the necessary conditions are met, a lower tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is -2.50, then the p-value is 0.0062.

Accepted Answer

A) True 
 B)False

Question 10

In testing   vs.   using a significance level equal to .05, the critical value that will be used to conduct the test is z = 1.645.

Accepted Answer

A) True 
 B)False

Question 11

A two-tailed test of hypothesis for a population mean   with a significance level   equal to .05 will have a critical value z equal to .475.

Accepted Answer

A) True 
 B)False

Question 12

A hypothesis that specifies a range of values for the unknown parameter is called an interval estimate.

Accepted Answer

A) True 
 B)False

Question 13

In a two-tail test for the population proportion, if the null hypothesis is rejected when the alternative hypothesis is false, a Type I error is committed.

Accepted Answer

A) True 
 B)False

Question 14

In selecting the sample size to estimate the population proportion p, if we have no knowledge of even the approximate values of the sample proportion   , we:

Accepted Answer

A)  take another sample and estimate 
B)  take two more samples and find the average of their 
C)  let=0.50 
D)  let=0.95 
E)  let=0.05 
A)  take another sample and estimate 
B)  take two more samples and find the average of their 
C)  let=0.50 
D)  let=0.95 
E)  let=0.05

Question 15

The null hypothesis is a vehicle for making startling new claims that contradict the conventional wisdom, that assert "guilt without a reasonable doubt."

Accepted Answer

A) True 
 B)False

Question 16

A sample of size 150 from population 1 has 40 successes. A sample of size 250 from population 2 has 30 successes. The value of the test statistic for testing the null hypothesis that the proportion of successes in population one exceeds the proportion of successes in population two by 0.05 is:

Accepted Answer

A)  1.645 
B)  2.327 
C)  1.960 
D)  1.977 
E)  1.772 
A)  1.645 
B)  2.327 
C)  1.960 
D)  1.977 
E)  1.772

Question 17

Which of the following exemplifies a Type I error of incorrectly rejecting a true null hypothesis?

Accepted Answer

A)  Interrupting the production process in order to adjust machinery that needs no adjusting. 
B)  Switching to a new supplier of raw materials although the performance of the old one was satisfactory. 
C)  Condemning a firm for ignoring pollution standards even though it has done no such thing. 
D)  All of these. 
E)  None of these. 
A)  Interrupting the production process in order to adjust machinery that needs no adjusting. 
B)  Switching to a new supplier of raw materials although the performance of the old one was satisfactory. 
C)  Condemning a firm for ignoring pollution standards even though it has done no such thing. 
D)  All of these. 
E)  None of these.

Question 18

In estimating the difference between two population means, the following summary statistics were found:           and   Based on these results, the point estimate of   is .70.

Accepted Answer

A) True 
 B)False

Question 19

In testing the hypotheses
H0: p1 - p2 = 0.10 vs.
Ha:   .
Use the following statistics, where x1 and x2 represent the number of Dial Soap sales in the two samples, respectively.
n1 = 150, x1 = 72
n2 = 175, x2 = 70
What conclusion can we draw at the 5% significance level?
Test statistic = ______________
Critical Value(s) = ______________
Conclusion: ______________
What is the p-value of the test?
p-value = ______________
Explain how to use the p-value to test the hypotheses.
____________________________
Estimate with 95% confidence the difference between the two population proportions.
______________
Interpret and explain how to use the confidence interval to test the hypotheses.
__________________________________________

Accepted Answer

1.449; 1.96, -1.96; Do not reject H₀; 0.1

Question 20

After calculating the sample size needed to estimate a population proportion to within 0.04, your statistics professor told you the maximum allowable error must be reduced to just .01. If the original calculation led to a sample size of 800, the sample size will now have to be:

Accepted Answer

A)  800 
B)  3200 
C)  12,800 
D)  6400 
E)  1600 
A)  800 
B)  3200 
C)  12,800 
D)  6400 
E)  1600

The first step in hypothesis testing is always:

Which of the following is an example of a null hypothesis?

For a fixed sample size n, as the probability of a Type II error decreases, the probability of a Type I error increases.

In testing vs. the level of significance must be twice as large as when testing vs. .

A Type I error for a statistical test is committed if we reject the null hypothesis when it is true.

If we reject the null hypothesis , we conclude that there is not enough statistical evidence to infer that the population proportions are equal.

Consider testing the hypothesis: . If the value of the test statistic is equal to 1.36, then the p-value is:

In constructing a confidence interval estimate for the difference between two population proportions, we:

When the necessary conditions are met, a lower tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is -2.50, then the p-value is 0.0062.

In testing vs. using a significance level equal to .05, the critical value that will be used to conduct the test is z = 1.645.

A two-tailed test of hypothesis for a population mean with a significance level equal to .05 will have a critical value z equal to .475.

A hypothesis that specifies a range of values for the unknown parameter is called an interval estimate.

In a two-tail test for the population proportion, if the null hypothesis is rejected when the alternative hypothesis is false, a Type I error is committed.

In selecting the sample size to estimate the population proportion p, if we have no knowledge of even the approximate values of the sample proportion , we:

The null hypothesis is a vehicle for making startling new claims that contradict the conventional wisdom, that assert "guilt without a reasonable doubt."

A sample of size 150 from population 1 has 40 successes. A sample of size 250 from population 2 has 30 successes. The value of the test statistic for testing the null hypothesis that the proportion of successes in population one exceeds the proportion of successes in population two by 0.05 is:

Which of the following exemplifies a Type I error of incorrectly rejecting a true null hypothesis?

In estimating the difference between two population means, the following summary statistics were found: and Based on these results, the point estimate of is .70.

After calculating the sample size needed to estimate a population proportion to within 0.04, your statistics professor told you the maximum allowable error must be reduced to just .01. If the original calculation led to a sample size of 800, the sample size will now have to be:

Describing Data With Graphs

Describing Data With Numerical Measures

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

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Exam 9: Large-Sample Tests of Hypotheses

The first step in hypothesis testing is always:

Which of the following is an example of a null hypothesis?

For a fixed sample size n, as the probability of a Type II error decreases, the probability of a Type I error increases.

In testing vs. the level of significance must be twice as large as when testing vs. .

A Type I error for a statistical test is committed if we reject the null hypothesis when it is true.

If we reject the null hypothesis , we conclude that there is not enough statistical evidence to infer that the population proportions are equal.

Consider testing the hypothesis: . If the value of the test statistic is equal to 1.36, then the p-value is:

In constructing a confidence interval estimate for the difference between two population proportions, we:

When the necessary conditions are met, a lower tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is -2.50, then the p-value is 0.0062.

In testing vs. using a significance level equal to .05, the critical value that will be used to conduct the test is z = 1.645.

A two-tailed test of hypothesis for a population mean with a significance level equal to .05 will have a critical value z equal to .475.

A hypothesis that specifies a range of values for the unknown parameter is called an interval estimate.

In a two-tail test for the population proportion, if the null hypothesis is rejected when the alternative hypothesis is false, a Type I error is committed.

In selecting the sample size to estimate the population proportion p, if we have no knowledge of even the approximate values of the sample proportion , we:

The null hypothesis is a vehicle for making startling new claims that contradict the conventional wisdom, that assert "guilt without a reasonable doubt."

A sample of size 150 from population 1 has 40 successes. A sample of size 250 from population 2 has 30 successes. The value of the test statistic for testing the null hypothesis that the proportion of successes in population one exceeds the proportion of successes in population two by 0.05 is:

Which of the following exemplifies a Type I error of incorrectly rejecting a true null hypothesis?

In estimating the difference between two population means, the following summary statistics were found: and Based on these results, the point estimate of is .70.

After calculating the sample size needed to estimate a population proportion to within 0.04, your statistics professor told you the maximum allowable error must be reduced to just .01. If the original calculation led to a sample size of 800, the sample size will now have to be:

Describing Data With Graphs

Describing Data With Numerical Measures

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters